<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>块级元素</title>
    <style>
      .container {
        padding: 20px;
      }
    </style>
  </head>
  <body>
    <!--
    1. 独占一行(即使设置宽度也是独占一行)
    2. 继承父级元素宽度(宽度是指)
    -->
    <h1></h1>
    <h2></h2>
    <div class="container">
      <div></div>
    </div>
    <span><div>111</div></span>
    <script>
  let str = "sssssssss"
  str[0]
    </script>
  </body>
</html>
